(This lecture is another longish one, so
it might just be better to print it out for easier reading)

If one had to list the eight or ten most
influential thinkers in the past 2500 years, Immanuel Kant's name would
almost certainly be on that list.

Kant's writings are deeply profound, difficult
to understand, and rich with complexities. In graduate school I took
a full course on Immanuel Kant. Graduate courses presumably cover more
material than undergraduate courses and yet this course covered only
one thinker. In that entire course we read only one of Kant's books, The
Critique of Pure Reason, a rich and difficult book, and in that
entire course we got through less than half of The Critique.
The reason is that it takes a great deal of time and effort to work
through and understand the philosophy of Immanuel Kant. The effort
expended in understanding Kant is, however, immensely worth it. (For
a well-written summary of Kant's metaphysic, you might also read Schopenhauer's
excellent eight-page summary of Kant which he adds as an appendix at
the end of The World as Will and Representation, pp 417-25.)

In this introductory course, however, we
will look at only two of Kant's many ideas, and we are going to look
at these two because understanding them is an important prerequisite
to understanding the writings of Arthur Schopenhauer. Both of these
ideas derive from Kant's analysis of the rationalist and empiricist
philosophers who immediately preceded him. (See the historical/philosphical
map.) The two ideas we will examine in this lecture are, in this
order, 1) Kant's big question, and 2) the categories of perception.

I. The Big Question:

The big question is, stated simply, "Is
it possible to know what is ultimately real?" Or "Is metaphysics
even possible?" (Metaphysics, for our purposes here, is the discipline
which attempts to understand the ultimate nature of being, i.e., which
tries to know what is really and ultimately real.) This question is
not a particularly new one, but Kant's phrasing of the question turns
out to be what is significant. He asks the question in this way: "Are
synthetic, a priori judgments about noumena possible?" In
order to understand what this question is asking, we will need to look
at some of the unfamiliar words in it.

a. phenomenal/noumenal
Let's begin with the word noumena, plural of noumenon. This distinction between
phenomenon and noumenon is basically the same as the distinction between
appearance and reality. The phenomenal and the noumenal are two aspects
of The Real, viz., the aspect which appears to us when we perceive
it, and the aspect that is actually really real. The physicists,
for example, tell us that even though the chair appears to be impenetrable
and solid, in fact it is made up of molecules and atoms which are themselves
made almost entirely of empty space. So the way a thing appears to
our senses may not be, at least according to physics, the same as the
way the thing really actually is. The phenomenal aspect of a thing may
be entirely different than the noumenal thing, the thing as it really
truly is.

Thus, phenomenon and noumenon are thus two
aspects of the real, as in this little chart:

Aspects of the Real

Phenomenon(a)

Noumenon(a)

And Kant's question is asking whether it
is possible to know the noumenal aspect of things. It is obviously
possible to know the phenomenal aspect of things, because the phenomenal
is what shows, it is what appears to us ("phenomenon" is
from the Greek word which means "to show"). But the question
before us is whether it is also possible to know what is really real.
Berkeley claimed that the only things that were really real were perceptions
and minds, and Hume believed that everything we experience is really
only a perception, and that what we think of as our self or identity
is not really real at all.

So is it even possible to know what's really
real? That is what Kant is asking.

b. a posteriori/a priori

Let's next consider the terms a priori and a
posteriori.

Ways of Knowing

a posteriori

a priori

As the chart above indicates, a posteriori and a
priori are two ways of knowing. Experiential, or a posteriori,
knowing is knowing based on experience, i.e., knowledge that is logically
posterior to (and grounded in) experience. It is empirical knowledge,
therefore, and derives from our experience.

Experiential knowledge, of course, can give
us knowledge only of appearances, since our experience shows us only
how things appear to our experience. So a posteriori knowledge
can give us knowledge only of the phenomenal aspect of things, never
of the noumenal.

What this means is that if we are ever to
have knowledge of the noumenal, of what is really real, that knowledge
will have to be based on some non-a posteriori kind of knowledge.
Kant calls such knowledge (if there is any such thing) a priori knowledge
because it is not based on experience, i.e., is logically prior
to experience. In other words, if we are to have knowledge of the noumenal,
it will have to come from some form of a priori knowledge because a
posteriori knowledge gives us only knowledge of how things appear
(phenomenally) to our senses.

So Kant's question is thus asking whether
it is possible to have a priori knowledge of the noumenal.

Now does any such thing as a priori knowledge
even exist, i.e., knowledge that is not logically grounded in experience?
Kant thinks that there is at least one example of a priori knowledge,
and that is mathematics. We do not learn about square roots and decimals,
Kant thinks, by looking around in the world. We do not find such things
in the world. Knowledge of these things is not based in our experience
of the world, but is based instead on some non-experiential grounding.
Whether Kant is correct in this claim about mathematics is almost irrelevant
for our purposes, though (some mathematicians agree with him and some
don't). Because whether he is right or wrong about mathematics, his
big question still requires that in order to know what is really real,
beneath the appearances, we will need to come to knowledge of that
noumenal reality by means of some kind of non-empirical a priori knowledge.

So Kant's question is thus asking whether a
priori knowledge of the noumenal is even possible.

c. synthetic/analytic

And finally, as in the chart below, there
are two basic kinds of propositions or statements, synthetic propositions
and analytic propositions.

Kinds of Propositions

synthetic

analytic

Every proposition has basically two terms
in it, arranged in the same basic form: Subject
is Predicate. An example of a
standard proposition would be "The
ball is red." What this
proposition is proposing is that these two terms, ball and red,
should be thought of as going together. When you tell me that the ball
is red you are asking me to put two quite different concepts together.
You are proposing that I synthesize - put together - two different
concepts, ball and red. "The
ball is red" is considered
a synthetic proposition because it is proposing that I synthesize two
quite different concepts.

An analytic proposition, on the other hand,
is quite different than this. Consider the proposition "A
bachelor is an unmarried male" (this
is actually Kant's own example; he was a bachelor all his life). Notice
the two concepts in this proposition, "bachelor" and "unmarried
male." Those are not two
different concepts at all, but in fact are exactly the same concept
just expressed in two different ways. So when someone says "A
bachelor is an unmarried male" you learn absolutely nothing new.
You've heard only a tautology. You've heard a proposition that simply
analyzes the concept of "bachelor," which is why it is called
an analytic proposition.

In the same way we could create an analytic
proposition about noumenal reality. For example, we could say "The
noumenal is what is really real." Again, the two concepts in that
proposition, "noumenal" and "really real" are the
same exact concept just expressed in two different ways. So that proposition
doesn't tell you diddly squat about what noumenal reality is, and for
that reason it's really pretty useless as a proposition.

So Kant's question, therefore, is asking
whether synthetic a priori propositions about noumena are possible.
Or translated it could read thus: is it possible to have real knowledge
about what is ultimately really real, and that knowledge cannot be
based on experience since experience gives us knowledge only of appearances?

That's Kant's question, and his manner of
asking it is more important than any answers he may have attempted
himself.

Post-Kantian philosophers have answered the
question in various ways, as you can see by consulting the philosophical
map I've put together for you. Our interest will be primarily in Schopenhauer's
answer to this question, because out of Schopenhauer's thought comes
much of what is interesting in Western thought ever since then (as
you will see on the philosophical map).

II. The Categories of Perception

You recall the little binary computers discussing
whether the world out there really is made up of only ones and zeroes?
They thought it must be because everything they experience actually
is in the form of ones and zeros. However, the real reason they experience
the world that way is because those are the only two categories their
processors are capable of recognizing.

Immanuel Kant believes that we humans have
more categories of perception than the binary computers have, but that
we still perceive everything in terms of our particular categories
because our minds can register only what our minds are capable of registering.

a.) Let's consider time, one of the primary
categories that Kant believes shapes all our perceptions, just as ones
and zeroes shape the perceptions of binary computers. (The category
of time includes such notions as now and then, earlier and later, before
and after, fast and slow, duration, and so on.) Time shapes all our
perceptions because our minds are simply incapable of having any perceptions
except those that are conditioned by time. We are, of course, capable
of having perceptions in which time acts in some very strange and unusual
ways. For example, in Kurt Vonnegut's Slaughterhouse Five, the
author tells us that "Billy Pilgrim came unstuck in time." He
sometimes was living in the 1950s or 60s, and other times was in the
midst of World War II in Germany. And we've all experienced time as
seeming to slow down or speed up, but none of us, says Kant, has ever
had an experience that is not conditioned by time.

This fact alone, viz., that every single
actual experience we have ever had, without exception, has occurred
in time, ought to make us suspicious that time is a human construct,
something our minds must add to experience in order for the experience
even to register with us. (As the bumper sticker says: Time is the
mind's way of arranging things so that everything doesn't happen all
at once.) So the fact that the entirety of our actual experience occurs
in time ought to make us suspicious that time is something in us rather
than out in the world.

But even more important, our minds are incapable
of even imagining what a time-less experience would be like. The fact
that we cannot even imagine a non-time-conditioned perception ought
to make us even more suspicious that time is a condition our minds
add to perceptions. The way Kant says it is this: the fact that all
of our actual and all of our possible experience is conditioned by
time is an indication that time is one of the mind's necessary categories
of perception.

b.) The situation is similar with regard
to the concept of space. Space conditions every experience we have
ever had. (Space includes notions such as here and there, large and
small, near and far, up and down, high and low, around, proximity,
and so forth.) The fact that every actual experience we have ever had
has been conditioned by space ought to make us suspicious that space
is a human construct, something our minds must add to experience in
order for it even to register with us. (I've never seen a bumper sticker
that says this, but there should be one: Space is the mind's way of
arranging things so that everything doesn't happen all in the same
place.)

But even more important, our minds are simply
incapable of even imagining what a space-less experience would be like.
The fact that we cannot even imagine a non-space-conditioned perception
ought to make us even more suspicious that space is a condition our
minds add to perceptions. The way Kant says it is this: the fact that
all of our actual and all or our possible experience is conditioned
by space is an indication that space is one of the mind's necessary
categories of perception.

Kant considers space and time to be the two
primary conditioners of all our experience, the two "transcendental
forms of perception."

Transcendental Forms of Perception

Time

Space

But in addition to these two transcendental
forms of perception, twelve other categories also condition our experience.

In the following table you can see what those
other categories are. We will not spend time on these other categories
except to single out the middle one under Relation: viz., cause and
effect.

The Categories of Perception

Of Quantity

Of Quality

Of Relation

Of Modality

Unity

Reality

Inherence and Subsistence

Possibility - Impossibility

Plurality

Negation

Causality
and Dependence (cause & effect)

Existence
- Non-existence

Totality

Limitation

Community (reciprocity
between agent & patient)

Necessity
- Contingence

You will recall that Kant had said that reading
Hume woke him from his "dogmatic slumbers." He fully agreed
with Hume's discovery that we never directly experience cause and effect.
That is, we never experience the actual causing happening, but instead
experience only the regular contiguity of two events that are juxtaposed
with each other in time (e.g., flipping the switch up, and then seeing
the light go on). Kant says that Hume was right about that: we do not
experience causing. But we human beings do need to think in terms of
cause and effect because it is simply one of the categories of our
mind. Just as binary computers think in terms of ones and zeroes, so
we think in terms of space, time, cause and effect, etc. It's just
the way we're built, says Kant.

In any case, what this all means for Kant
is that our entire experienced world, i.e., our entire phenomenal world
as it appears to us in our daily experience, is conditioned by space
and time, by cause and effect, and by all the other eleven categories
of our minds.

We can thus say that the whole multiplicity
of the phenomenal world - what Buddhism refers to as the ten thousand
things - is "the temporal, spatial, causal manifold."

This phrase -- "the temporal, spatial,
causal manifold" -- becomes significant in Schopenhauer's thought,
because he pretty much buys most of what Kant says here about the categories
of perception.. So the question for Schopenhauer becomes, is it possible
for us to know what is ultimately real beyond the appearances, beyond
the temporal, spatial, causal many-fold multiplicity of our experience?

Schopenhauer believes the answer to this
question is yes it is possible, and that the ultimate noumenal reality
which lies behind all the appearances is, as you will see in reading
him, Der Wille.